Fourth-generation (4G) mobile communications concepts and technologies are beginning to evolve. In the simplest form, 4G consists of an evolution beyond the third-generation (3G) cellular communication systems now at or near deployment worldwide. Cellular communications has evolved from the original analog formats, called 1G, to the digital formats now in use and labeled 2G, to 2.5G and 3G. Most treatments of 4G involve a much more expansive view of the wireless services that are possible, and often encompass a vision of seamless, ubiquitous connectivity with cellular networks, wireless local area networks (WLANs), and wireless personal area networks (WPANs, wireless networks that cover a very short distance, and may be used to interconnect devices on one's person or very close vicinity), as well as the connections into fixed wireless and wired networks.

Applications and services available through any network are also made available on any other wireless network. The wireless world, a term first used by the Wireless World Research Forum (WWRF) in its Book of Visions to describe 4G, would be a fundamentally better wireless communications and networking system than those currently in use or in deployment.